Implement comprehensive task management system with GITEA integration

Replace mock endpoints with real database-backed task management:
- Add tasks table with full relationships and indexes
- Create generic task management service supporting multiple sources
- Implement GITEA integration service for issue synchronization
- Add task creation, retrieval, assignment, and status updates

Database schema changes:
- New tasks table with external_id mapping for GITEA/GitHub/Jira
- Foreign key relationships to teams and agents
- Task workflow tracking (claimed_at, started_at, completed_at)
- JSONB fields for labels, tech_stack, requirements

Task management features:
- Generic TaskFilter with pagination and multi-field filtering
- Automatic tech stack inference from labels and descriptions
- Complexity scoring based on multiple factors
- Real task assignment to teams and agents
- GITEA webhook integration for automated task sync

API endpoints now use real database operations:
- GET /api/v1/tasks (real filtering and pagination)
- GET /api/v1/tasks/{id} (database lookup)
- POST /api/v1/tasks/ingest (creates actual task records)
- POST /api/v1/tasks/{id}/claim (real assignment operations)

GITEA integration includes:
- Issue-to-task synchronization with configurable task labels
- Priority mapping from issue labels
- Estimated hours extraction from issue descriptions
- Webhook processing for real-time updates

This removes the major mocked components and provides
a foundation for genuine E2E testing with real data.

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

migrations/002_add_tasks_table.down.sql

@@ -0,0 +1,11 @@
+-- Rollback tasks table creation
+ALTER TABLE teams DROP COLUMN IF EXISTS current_task_id;
+DROP INDEX IF EXISTS idx_tasks_external_id_source;
+DROP INDEX IF EXISTS idx_tasks_created_at;
+DROP INDEX IF EXISTS idx_tasks_priority;
+DROP INDEX IF EXISTS idx_tasks_repository;
+DROP INDEX IF EXISTS idx_tasks_assigned_agent;
+DROP INDEX IF EXISTS idx_tasks_assigned_team;
+DROP INDEX IF EXISTS idx_tasks_source_type;
+DROP INDEX IF EXISTS idx_tasks_status;
+DROP TABLE IF EXISTS tasks;

migrations/002_add_tasks_table.up.sql

@@ -0,0 +1,57 @@
+-- Tasks table for generic task management
+-- Supports GITEA, GitHub, Jira, and other task sources
+CREATE TABLE tasks (
+    id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
+    external_id VARCHAR(255) NOT NULL, -- GITEA issue ID, GitHub issue ID, etc.
+    external_url TEXT NOT NULL, -- Full URL to external task
+    source_type VARCHAR(50) NOT NULL DEFAULT 'gitea', -- 'gitea', 'github', 'jira', 'manual'
+    source_config JSONB DEFAULT '{}', -- Source-specific configuration
+    
+    -- Core task data
+    title VARCHAR(500) NOT NULL,
+    description TEXT,
+    status VARCHAR(50) NOT NULL DEFAULT 'open',
+    priority VARCHAR(20) NOT NULL DEFAULT 'medium',
+    
+    -- Assignment and team data
+    assigned_team_id UUID REFERENCES teams(id) ON DELETE SET NULL,
+    assigned_agent_id UUID REFERENCES agents(id) ON DELETE SET NULL,
+    
+    -- Repository and project context
+    repository VARCHAR(255), -- e.g., "owner/repo" 
+    project_id VARCHAR(255),
+    
+    -- Task metadata
+    labels JSONB DEFAULT '[]',
+    tech_stack JSONB DEFAULT '[]',
+    requirements JSONB DEFAULT '[]',
+    estimated_hours INTEGER,
+    complexity_score FLOAT,
+    
+    -- Workflow tracking
+    claimed_at TIMESTAMP WITH TIME ZONE,
+    started_at TIMESTAMP WITH TIME ZONE,
+    completed_at TIMESTAMP WITH TIME ZONE,
+    
+    -- Timestamps
+    created_at TIMESTAMP WITH TIME ZONE DEFAULT NOW(),
+    updated_at TIMESTAMP WITH TIME ZONE DEFAULT NOW(),
+    external_created_at TIMESTAMP WITH TIME ZONE,
+    external_updated_at TIMESTAMP WITH TIME ZONE,
+    
+    -- Constraints
+    UNIQUE(external_id, source_type) -- Prevent duplicate external tasks
+);
+
+-- Indexes for performance
+CREATE INDEX idx_tasks_status ON tasks(status);
+CREATE INDEX idx_tasks_source_type ON tasks(source_type);
+CREATE INDEX idx_tasks_assigned_team ON tasks(assigned_team_id);
+CREATE INDEX idx_tasks_assigned_agent ON tasks(assigned_agent_id);
+CREATE INDEX idx_tasks_repository ON tasks(repository);
+CREATE INDEX idx_tasks_priority ON tasks(priority);
+CREATE INDEX idx_tasks_created_at ON tasks(created_at);
+CREATE INDEX idx_tasks_external_id_source ON tasks(external_id, source_type);
+
+-- Update teams table to link back to tasks
+ALTER TABLE teams ADD COLUMN IF NOT EXISTS current_task_id UUID REFERENCES tasks(id) ON DELETE SET NULL;